Chip-scale gyroscope using silicon-nitride waveguide resonator with a Q factor of 100 million

Grant, Matthew J.; Vigneron, Pierre-Baptiste; Feshali, Avi; Jin, Warren; Abrams, Nathan C.; Paniccia, Mario; Digonnet, Michel J. F.

doi:10.1117/12.2617219

Cited by 6 publications

(11 citation statements)

References 11 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…4 show that the multi-turn gyroscope was dominated by LFN when the backscattering coefficient of the probed resonance was small (ab lower than about -80 dB/mm). The same noise analysis performed on the racetrack gyro in [9] showed that when the backscattering coefficient was comparably small, the two-arm ARW was proportional to √ab, i.e., the gyro output was dominated by backscattering noise. Therefore, the longer length and lower finesse of the multi-turn gyro successfully reduced the backscattering noise compared to the racetrack gyro, to the point where the gyro output is now limited by the (lower) laser-frequency noise.…”

Section: Experimental Setup and Resultsmentioning

confidence: 89%

“…The first chip-scale ring gyroscope that was fabricated and tested had a single-turn racetrack shape 2 mm by 18 mm, with a perimeter is 37 mm and the equivalent area of a circular ring of a 5.8-mm radius. 9 The racetrack waveguide has a propagation loss of 0.4 dB/m at wavelengths near 1550 nm, resulting in an intrinsic Q factor of one million and a finesse F of 1270. The lowest measured ARW of this device is 80 deg/h/√Hz, and it is limited by backscattering noise.…”

Section: Silicon-nitride Gyroscope Designsmentioning

confidence: 99%

“…The lowest measured ARW of this device is 80 deg/h/√Hz, and it is limited by backscattering noise. 9 When developing the second-generation of chip-scale ring gyroscope, it was important to reduce the backscattering noise further. One solution was to reduce the circulating power of the backreflected signal by reducing the finesse of the ring.…”

Section: Silicon-nitride Gyroscope Designsmentioning

confidence: 99%

“…One approach to reducing the finesse is to increase the length of the ring. Another solution for reducing the backscattering noise was to identify a resonance that has an even lower backscattering coefficient than the lowest reported in [9]. This can be potentially accomplished by decreasing the FSR of the resonator, which means that over a given frequency range, more resonances are available, and therefore there is a greater chance of finding a resonance with a record-low backscattering coefficient.…”

Section: Silicon-nitride Gyroscope Designsmentioning

confidence: 99%

“…At a wavelength of 1560.76 nm, a resonance was found with a backscattering coefficient of -96 dB/mm, which is similar to the lowest backscattering coefficient found on the racetrack gyro (-98 dB/mm). 9 Unless otherwise specified, all tests on this new gyroscope were carried out on this resonance. At this wavelength, the power coupling ratio of the ring coupler was close to the critical coupling, a condition that maximizes the sensitivity to rotation (but does not necessarily minimize the ARW, hence some optimization might be possible in future work).…”

Section: Silicon-nitride Gyroscope Designsmentioning

confidence: 99%

See 4 more Smart Citations

High-Q silicon nitride resonator gyroscope interrogated with broadband light

Zawada

Feshali²,

Jin³

et al. 2023

Quantum Sensing, Imaging, and Precision Metrology

Self Cite

View full text Add to dashboard Cite

Advancements in silicon photonics technology have resulted in significant progress toward tactical-grade chip-scale optical gyroscopes for applications such as inertial navigation for a range of self-driving vehicles. Our first generation of gyro, reported a year ago, was a resonant ring gyro fabricated with an ultra-low-loss silicon-nitride waveguide in a racetrack shape with a perimeter of 37 mm and a finesse of 1270. When the laser frequency was tuned to interrogate the resonance with the lowest backscattering coefficient, and balanced detection was implemented to reduce common noise in the two output signals, the angular random walk (ARW) was measured to be 80 deg/h/√Hz, and the gyro output was dominated by backscattering noise. The second-generation reported here utilizes a longer ring to further reduce backscattering noise. The ring resonator is a circular spiral with 33 turns, a length of 1.2 m, and a finesse of 29. When interrogated with a narrow-linewidth laser like the racetrack gyro, it has a measured ARW of 210 deg/h/√Hz dominated by laser-frequency noise. The ARW is higher than that of the racetrack gyro because the balanced detection was not as effective (13.2 dB of common noise rejection compared to 18 dB in the racetrack gyro). Tests in a vacuum indicate that environmental fluctuations do not contribute to the noise, and that most of the measured drift (3,500 deg/h) has an optical and/or electronic origin. We also report the noise performance of the racetrack gyro interrogated in a Sagnac interferometer probed with broadband light. This configuration was inspired by a recent publication from Shanghai Jiao Tong University that reports a resonant fiber optic gyroscope interrogated with broadband light with a measured ARW that meets tactical-grade requirements. The advantages of this interrogation technique are that it eliminates the need to stabilize the resonator, it reduces the component count, and by making use of incoherent light, it reduces the backscattering noise. The measured ARW of the racetrack gyro interrogated with broadband light was dominated by excess noise at large detected powers, and it was a factor of ~900 larger than the ARW of the same racetrack gyro interrogated with the laser. The reason for this increase in ARW is that the advantage of having a high-finesse resonator is lost when the ring is interrogated with broadband light, and the sensitivity is reduced by a factor of the finesse compared to the same ring resonator interrogated with a laser. This reduction in sensitivity is demonstrated experimentally. Achieving tactical-grade requirements will require returning to a laser interrogation, improving the balanced detection scheme to achieve a noise cancellation of 25 dB or better, and optimizing the laser linewidth to minimize both laser frequency noise and backscattering noise.

show abstract

Section: Experimental Setup and Resultsmentioning

confidence: 89%

Section: Silicon-nitride Gyroscope Designsmentioning

confidence: 99%

Section: Silicon-nitride Gyroscope Designsmentioning

confidence: 99%

Section: Silicon-nitride Gyroscope Designsmentioning

confidence: 99%

Section: Silicon-nitride Gyroscope Designsmentioning

confidence: 99%

See 3 more Smart Citations